If $x \star y = 8x-4y$ and $x \triangleright y = 3x-5y$, find $-3 \star (2 \triangleright 4)$.
Solution: First, find $2 \triangleright 4$ $ 2 \triangleright 4 = (3)(2)-(5)(4)$ $ \hphantom{2 \triangleright 4} = -14$ Now, find $-3 \star -14$ $ -3 \star -14 = (8)(-3)-(4)(-14)$ $ \hphantom{-3 \star -14} = 32$.